This would provide a quick fix to a number of long standing issues with the drawing workbench, most notably the lack of hole and chamfer callouts.
When dimensions are created in drawings, Fusion is clearly referencing model parameters in order to display the correct value for the dimension. You can see this when you try and edit a dimension, it is displayed between chevron brackets and is highlighted in dark grey:
You can delete this tag/referece/code and add free text, but there is no way to add this back in. Logic would suggest that you would be able to look up the parameter name and type this back in manually, e.g. <d9> in the above example:
This does not work in Fusion however, typing <d9> into the dimension box simply shows the text "<d9>" rather than looking up the parameter value and showing "39".
Needless to say this is a pretty standard feature in most other CAD packages, and while parametrically referencing features in this way is quite cumbersome it would at least allow proper dimensioning of features, something which is impossible at the moment.